In an AC circuit there is real power and reactive power. Real power (which transmits actual power) is from the component of current that is in phase with the voltage. Reactive power (which transmits no power) is the current component that is 90 degrees out of phase with the voltage. The real power equals the RMS voltage times the RMS current times the cosine of the phase angle between the voltage and current.
A phase angle of 90 degrees occurs when driving a pure inductive or pure capacitive load. A pure inductor or capacitor dissipates no real power, only reactive power. You can thus see how you can have current and voltage with no real power.
The power company quantifies the value of real power with Power Factor. The Power Factor varies between 1, when the current is in phase with the voltage, to 0, when the current is 90 degrees out of phase with the voltage. Power companies obviously want to keep the PF as close to one as possible, to minimize useless reactive currents flowing in the power lines.
I see the conversation is still active, which is a good thing if it sheds light for the OP who started the thread.
Before I reply to your comment, it is with a heavy heart that I just this morning discovered one of my heroes has passed away. I have been inactive in my radio hobby for a couple of years now and have not done much reading on antennas and radio theory. A brilliant man, LB Cebik (W4RNL), an amateur radio guru who was anything but an amateur, went "silent key" last year. In doing some refresher reading I went to his website only to see he had passed away and that a commercial entity had taken his site over. At least it has free registration and hasn't become a pay site! Cebik freely passed along his knowledge and I would hate to see someone else profit from his legacy.
At any rate, you bring up real vs reactive power, and in fact you are correct that these two variables coexist in AC theory. But in backpeddling from your original thesis you further muddy the waters for the original OP, methinks. I do not know the OPs knowledge base, but assuming he is just starting to learn AC theory I think it is important to focus on the THEORY which encompasses quite a bit of applications, not limited to "power distribution" and power supply transformers.
You bring up real vs reactive and seem to imply that "real power" is some way more desireable than reactive power, or more "real", LOL, which is a deceptive word. If all electronic circuits were designed to energize light bulbs, turn a motor, etc, then you might have a point. However, this is not the case thankfully or my cellphone and radio equipment wouldn't work.
In radio, in fact, REACTIVE power is the desireable power and "real power" is what we seek to mitigate.
If the OP or anyone cares to register on Cebik's webiste, you can access the following URL:
https://www.cebik.com/content/a10/tales/name.html
Which talks in an introductory way about various antenna types. But no matter the design, antennas work on the same principle which is a demonstration of a nearly pure reactive element in an AC circuit, and in function behaves much like a tranformer at radio frequencies...except instead of inducing a current into another coil, the antenna induces radio waves into the surrounding environment.
It seems magical that a radio transmitting hundreds or thousands of watts of power into an antenna and transmission line system has little "visible" evidence of the power. We are used to seeing power at work in the form of mechanical movement, light, heat, etc. Well, no antenna is perfect and some RESISTIVE impedance occurs, causing SOME heat. However, if it is efficient we hope that the majority of the power makes its way into the ether as radio waves.
And that power IS demonstrable. We CAN see how significant it is. My QRP (5 watt or less) radios are capable of sending a signal hundreds, thousands of miles, to be received by another antenna (which behaves the same way in reverse when in RX mode) This is reactive power at work, desireable, predictable, measureable, and perfectly relevant to AC theory.
Again, the effects of "real power" in radio are to create heat in exchange for radio energy, which is an undesireable biproduct.
If you scroll down on this W4RNL webpage at the bottom, you will see a modelled depiction of the current and voltage distribution of a half wave "dipole" as well as "doublets". In the case of the dipole, at resonant frequency we have current and voltage distribution as such that along the length of the dipole from one element to the other, there is one half cycle of AC, with the instance of maximum current 90 degrees out of phase with maximum voltage, the peak voltage measured at the two ends of the dipole and current distributed along its length, maximum at the feedpoint.
The doublet is an antenna working at multiple wavelengths, with multiple points of peak current and peak voltage along its length. In amateur radio our "bands" are arranged somewhat optimally so that they are multiple wavelengths of each other, so doublets can be used as multi-band antennas. Optimally, the doublet working on a fequency which is a multiple of its resonant frequency (ie 160 meter dipole operating at 40 meters) the voltage and current peaks will still be evenly distributed along the elements, with the ends still being instances of peak voltage...only in this case the feedpoint may or may not be an instance of peak current or peak voltage.
Now, I realize I went into great detail about antennas and not coils and transformers, but the point is that AC theory has fundamentals that are applicable and critical for thorough understanding. Getting bogged down with 60 hz power distribution muddies the discussion. Unless the OP is only interested in becoming an electrician or engineer at a power plant, he needs to understand more than "real power" and should consider the applications of "reactive power".
